This is an eco-friendly, natural material hand warmer that can be reused in the microwave. Benefits of Rice Bran Hand Warmers: Promotes blood circulation Warming improves blood flow, balances the body, and supports body function. Relieves lower back pain, leg pain, and knee muscle pain Ideal for those tired from long hours of desk work or standing. Applying the hand warmer to the abdomen helps digestion and soothes abdominal discomfort. Eco-friendly and reusable for about 2 years. Inner bag: Outer bag: 100% cotton Finished size: 22 x 15 cm String: 70 cm on both sides Can be tied and used anywhere, such as the lower back, shoulders, and legs, making it ideal for areas of pain.